Archive for the Category » computing «

Sunday, August 04th, 2013 | Author:

I had a power outage affect my server’s large md Uvamizi array. Rather than let the server as a whole be down while waiting for it to complete an fsck, I had it boot without the large array so I could run the fsck manually.

Hata hivyo, when running it manually I realised I had no way of knowing how far it was and how long it would take to complete. This is especially problematic with such a large array. With a little searching I found the tip of adding the -C parameter when calling fsck. I couldn’t find this in the documentation however: fsckhelp showed no such option.

The option turns out to be ext4-specific, and thus shows a perfectly functional progress bar with a percentage indicator. To find the information, instead offsckhelp” au “man fsck”, you have to inputfsck.ext4help” au “man fsck.ext4”. 🙂

Kushiriki
Sunday, August 04th, 2013 | Author:

Historia

Mengi alikuwa iliyopita tangu mimi mwisho zilizotajwa yangu binafsi server – ni imeongezeka kwa kiwango kikubwa na mipaka (sasa ina 7TB md RAID6) na alikuwa karibuni imekuwa upya kwa Ubuntu Server.

Upinde alikuwa kamwe kosa. Arch Linux alikuwa tayari alinifundisha sana kuhusu Linux (na itaendelea kufanya hivyo kwenye desktop yangu nyingine). Lakini Arch dhahiri inahitaji muda zaidi na makini kuliko napenda kutumia katika server. Walau ningependa wanapendelea kuwa na uwezo wa kusahau kuhusu server kwa muda mpaka email kukumbusha anasema “um … kuna updates wanandoa unapaswa kuangalia, buddy.”

Nafasi si bure – na wala nafasi ya

nafasi ya kuhamia Ubuntu alikuwa na ukweli kwamba nilikuwa kukimbia nje ya SATA bandari, bandari required kuunganisha anatoa ngumu kwa mapumziko ya kompyuta – kwamba 7TB uvamizi safu matumizi mengi ya bandari! Mimi nilikuwa na hata kupewa mbali wangu sana zamani 200GB ngumu kuendesha kama Ni Akachukua moja ya bandari Wale. Mimi pia alionya kwamba mpokeaji disk ya SMART ufuatiliaji unahitajika ilikuwa ni uhakika. Kama workaround muda na ukosefu wa bandari SATA, Mimi nilikuwa na hata wamehamia OS seva na seti ya nne USB vijiti katika md RAID1. Crazy. Mimi najua. Mimi si furaha sana kuhusu kasi. Niliamua kwenda nje na kununua mpya kuaminika ngumu kuendesha na kadi SATA upanuzi kwenda nayo.

server cha msingi Arch kizigeu ilikuwa kutumia kuhusu 7GB ya disk. chunk kubwa ya kwamba ilikuwa wabadilishane faili, cached data na vinginevyo miscellaneous au unnecessary files. Kwa ujumla ukubwa halisi wa OS, ikiwa ni pamoja na /nyumbani folder, ilikuwa tu kuhusu 2GB. Hii ilisababisha yangu kuangalia ndani ya super-haraka SSD kuendesha gari, kufikiri labda moja ndogo wanaweza kuwa hivyo gharama kubwa. Aligeuka kuwa gharama nafuu mashirika yasiyo ya SSD gari mimi naweza kupata kwa kweli gharama zaidi ya moja ya haya SSDs ndogo. Yay kwa ajili yangu. 🙂

Uchaguzi? Woah?!

Katika kuchagua OS, Ningependa tayari aliamua isingekuwa Arch. Kati ya mengine yote mgawanyo maarufu, Mimi nina zaidi ukoo na Ubuntu na CentOS. Fedora alikuwa pia uwezekano – lakini sikuwa umakini bado ni kuchukuliwa kwa seva. Ubuntu alishinda duru ya.

uamuzi ijayo mimi alikuwa na kufanya hawakuwa kutokea kwangu mpaka Kuenenea (Ufungaji wa Ubuntu mchawi) aliuliza ni wa kwangu: Jinsi ya kuanzisha partitions.

Nilikuwa mpya ya kutumia SSDs katika Linux – Mimi nina pamoja na ufahamu wa hasara za si kutumia yao kwa usahihi, zaidi kutokana na hatari ya longevity maskini kama vibaya.

Sikutaka kutumia ari byta kizigeu. Mimi mpango juu ya kuwaendeleza Motherboard seva / CPU / kumbukumbu si mbali sana katika siku zijazo. Kulingana na kwamba mimi niliamua kuweka byta katika faili byta juu ya uvamizi zilizopo MD. wabadilishane hautakuwa hasa kufunga lakini madhumuni yake itakuwa tu kwa ajili ya tukio nadra kwamba wakati kitu wamekwenda vibaya na kumbukumbu si inapatikana.

Hii basi kushoto kwangu kutoa mizizi njia 60GB kamili nje ya Intel 330 SSD. Nikaziangalia kutenganisha / nyumbani lakini alionekana tu kidogo pointless, aliyopewa jinsi kidogo ilitumika katika siku za nyuma. Mimi kwanza kuanzisha kizigeu na LVM – kitu Nimekuwa hivi karibuni wamekuwa wakifanya wakati mimi kuanzisha sanduku Linux (kweli, hakuna udhuru si kwa matumizi LVM). Wakati got sehemu ambapo napenda configure mfumo wa faili, Mimi clicked drop-down na instinctively kuchaguliwa ext4. Kisha mimi niliona btrfs katika orodha hiyo. Hutegemea!!

Lakini nini?

Btrfs (“siagi-EFF-ess”, “bora-EFF-ess”, “nyuki-mti-EFF-ess”, au chochote wewe dhana juu ya siku) ni mfumo wa faili jipya maendeleo ili kuleta Linux’ mfumo wa faili uwezo nyuma kufuatilia kwa sasa mfumo wa faili tech. Mfalme-ya-the-Hill zilizopo mfumo wa faili, “ext” (toleo la sasa kuitwa ext4) ni nzuri – lakini ni mdogo, kukwama katika dhana ya zamani (kufikiri ya bidhaa mpya F22 Raptor vs. an F4 Phantom na jaribio nusu-jested katika kuboresha equivalency) na kuna uwezekano wa kuwa na uwezo wa kushindana kwa muda mrefu sana na filesystems karibu zaidi Enterprise kama vile Oracle ZFS. Btrfs bado ina njia ndefu ya kwenda na bado ni kuchukuliwa majaribio (kutegemea ambaye kuuliza na kile unahitaji makala). Wengi wanaiona kuwa imara kwa ajili ya matumizi ya msingi – lakini hakuna ni kwenda kufanya dhamana yoyote. Na, bila shaka, kila mtu ni kusema ya kufanya mtihani na backups!

Mooooooo

tofauti ya msingi kati ya ext na btrfs ni kwamba btrfs ni “Ng'ombe” au “Nakala Andika” mfumo wa faili. Hii ina maana kwamba data ni kweli kamwe makusudi overwritten na internals mfumo wa faili ya. Kama wewe kuandika mabadiliko kwenye faili, btrfs kuandika mabadiliko yako na eneo mpya ya vyombo vya habari kimwili na update kuyatumia ndani kwa kutaja eneo mpya. Btrfs huenda hatua zaidi kwa kuwa wale kuyatumia ndani (inajulikana kama metadata) ni pia Ng'ombe. Wazee matoleo ya ext ingekuwa tu overwritten data. Ext4 atatumia Journal kuhakikisha kwamba rushwa si kutokea lazima kuziba AC kuwa yanked nje wakati wengi inopportune. Matokeo ya journal katika idadi sawa ya hatua zinazohitajika kwa update data. Na SSD, vifaa inavyotumia kazi sawa ng'ombe mchakato bila kujali filesystem unatumia. Hii ni kwa sababu SSD anatoa hawawezi kweli overwrite data – wana kunakili data (pamoja na mabadiliko yako) na eneo mpya na kisha kufuta block zamani kabisa. optimization katika eneo hili ni kwamba SSD wanaweza hata kufuta block zamani lakini badala tu kufanya kumbuka kufuta kuzuia kwa wakati mmoja baadaye wakati mambo si hivyo busy. Matokeo ya mwisho ni kwamba SSD anatoa fit vizuri sana na filesystem ng'ombe na si kufanya kama vizuri na filesystems mashirika yasiyo ya ng'ombe.

Ili kufanya mambo ya kuvutia, Ng'ombe katika mfumo wa faili urahisi huenda mkono kwa mkono na kipengele aitwaye deduplication. Hii inaruhusu mbili (au zaidi) vitalu kufanana ya data kuhifadhiwa kwa kutumia tu nakala moja, kuokoa nafasi. Pamoja na ng'ombe, kama faili deduplicated ni iliyopita, pacha tofauti hazitaathirika kama data faili iliyopita mapenzi vimeandikwa kwa kuzuia tofauti kimwili.

Ng'ombe kwa upande hufanya snapshotting rahisi kutekeleza. Wakati snapshot ni alifanya mfumo tu rekodi snapshot mpya kama kuwa kurudia ya data na metadata ndani ya kiasi. Pamoja na ng'ombe, mabadiliko yanapofanyika, data snapshot wa anakaa intact, na mtazamo thabiti wa hali ya mfumo wa faili kwa wakati snapshot lilifanywa vinaweza kuendelezwa.

rafiki mpya

Pamoja na hapo juu katika akili, hasa kama Ubuntu imefanya btrfs inapatikana kama chaguo-kufunga wakati, I figured itakuwa wakati mzuri wa kupiga mbizi katika btrfs na kuchunguza kidogo. 🙂

Sehemu 2 kuja hivi karibuni …

Kushiriki
Monday, October 29th, 2012 | Author:

Inaonekana kwamba, katika hekima usio, Google kuwa kipengele cha usalama kinachoweza kuzuia maombi kutoka kupata au kutumia akaunti yako ya google. Naweza kuona jinsi hii inaweza kuwa tatizo kwa watumiaji wa Google, hasa wao Gtalk na Gmail watumiaji. Katika kesi yangu ilikuwa Pidgin kuwa suala hilo na Jabba huduma (ambayo ni sehemu ya kitaalam gtalk). Mimi kupatikana ufumbuzi baada kidogo kuchimba. Mimi alishangazwa na jinsi ya zamani ilikuwa na suala muda gani hulka hii ina kuwepo!

Ili kufungua akaunti na kupata maombi yako online, kutumia Google Captcha ukurasa hapa.

Kushiriki
Thursday, June 03rd, 2010 | Author:

Why I’ve left MTN

So I’ve been shopping around in a non-serious fashion in the last few months trying to figure out how best to leave MTN and how get the best deal for me. I don’t like MTN since I became anirate“, as I might call such a customer in the ISP industry. MTN’s Customer-Service Call Centre had rarely been helpful or knowledgeable on their own systems. The final straw however was when their systems let me screw myself over and Customer Service was as helpful as a dead redshirt:

I had a billing issue where, admittedly, it started of my own fault. MTN has a feature where you can call in to find out the amount owing on your account. Only, as Murphy would have it, this amount was si the amount owing on the account but the last amount that was billed.

So one month my account was about R900. I called the number, mis-heard R500, paid the amount I thought I should: R500. 15 days later MTN suspended my account. No wrong done, right? Wrong.

First off, I received no notification of any kind. An sms would make the most sense, especially since it would cost MTN almost no resources: “Your account xyz is in arrears by R400. Please contact blah blah blah”. They could phone me, they could email me, something, but nothing of the sort happened. Suspend without Prejudice. Thats the best way to get the customer’s attention!

Now, not only could I not make calls and sms’s, I could not receive calls or sms’s. Further, I could not even call MTN’s toll free phone number. I had to use someone else’s phone to get to the bottom of the problem. After two days of haggling I finally found a lady kind enough to re-enable the account. Ten days later my salary goes in, I call the same number and hear a number close toR900”. I think to myself maybe I should double-check juuuust in case I mis-heard. I call again, I hear the same number again. Right. Pay the R900. Fifteen days later, my phone is suspended AGAIN. WTH?

Remember what I mentioned earlier?: “this amount was si the amount owing on the account but the last amount that was billed.” So, in spite of the fact that the voice prompt specifically saysPress 3 for Balance Due; [Presses 3] ; The Total Outstanding Balance is; Nine; hundred; na; #whatever ; Rands; na; #whatever; cents”, I actually owed them R900 plus the R400 that I’d paid short the previous month. No, I do not know if MTN has fixed this. I no longer care. Since I figured this out I started waiting for paper statements to see how much was actually due. Interestingly, their paper statements were also wrong. Only they had the opposite problem: “This invoice: R1300in spite of the fact that on the next page it says opening balanceR400”, closing balanceR1300”. Pah! Is it fixed? Again, I don’t care.

I let them know I wasn’t renewing the contract and I’ve now already ported my number away to Virgin Mobile. Because I want to keep my number and port it elsewhere, the store said I could not putunsatisfactory serviceas the reason for ending the contract but that it should simply sayporting”. Apparently by putting anything else there they might notnoticethat I want it ported. WTF.

What next? (without MTN)

In my research I’ve found that contractdealsare most popular. Typically, you can get a R8000 phone for R800 per month over 24 months with R500-odd worth of airtime per month. This amounts to you paying R19 200 over a 24-month period for a phone worth R8000 which will be obsolete within 12 miezi. You will get some airtime every month so you might feel its not a complete loss. However you should also remember that it costs the cellular companies nothing when you make those phone calls. Faida.

There’s a better way

There are much cheaper contracts, contracts for between R50 and R200 which include cheapish phonesphones that work damned well as a phone but won’t let you play games on the train. Most of these contracts actually give you the same airtime value (sometimes more!) as what you are paying. So for R100 you might get R100 worth of airtime plus some free sms’s, and a cheapish phone. The best deals I’ve seen recently have all been for the Samsung STAR, an understated but good cell phone, available from a number of retailers for between R100 and R200 per month. In most cases the deals have included the full amount of airtime. Virgin Mobile has probably the best example here: The cost is R199 per month which includes R200 in airtime and 1000 sms’s (ndiyo, you read that rightone thousand!).

Virginal Service All the Way!

Another reason I’ve gone with Virgin Mobile is a little something no other service provider does: AmixedContract/Prepaid facility. I get R200 in airtime however, if I go over that, the extra just gets added to my invoice. With MTN this could go sky high without the option of a limit! With Virgin, because I asked, it has a limit of R300. Hata hivyo, I can still add prepaid airtime (with cellphone banking, nogal). No other service provider lets you do this!

Remember that R8000 cell phone I mentioned earlier? My plan is to get the Samsung STAR and spend less than R300 per month. I’ll have saved enough money to actually go and buy a more expensive phone (or laptop) with the cash I’ll have saved! Bila shaka, if you actually use that R800-worth of phone calls, I guess the best available deal is where you spend the R19200 anyway. Maybe at least with a more critical view on your choices you’ll save yourself a good amount of money in future. Good luck in your search for your best deal!

Kushiriki
Thursday, November 12th, 2009 | Author:

If you ever find yourself updating a single application in Arch Linux (a very bad idea, btw) and it upgrades readline you might end up seeing an error along the lines of:
/bin/bash: error while loading shared libraries: libreadline.so.5: cannot open shared object file: No such file or directory
Hopefully you still have a bash prompt open and you haven’t closed them all. If you still can, immediately run the following:
pacman -S bash
else you won’t be able to run bash any more because bash would still be linking to the old version of readline.

pia, in future, don’t run
pacman -Sy application
(python in my case)
instead, run:
pacman -Syu
which will ensure that all applications are upgraded.

Personally, I think that bash should have had a dependency set saying that it required the old specific version of readline and the same for the new bash, requiring the new version of readline. Regardless, rather play it safe. 😉

Kushiriki